JP7180401B2 - Rolling equipment and rolling method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rolling facility and a rolling method for rolling a steel plate.

Electrical steel sheets are widely used as iron core materials for transformers, generators, and electric motors. In recent years, non-oriented electrical steel sheets in particular have been used as motor materials for hybrid cars in order to improve the fuel efficiency of automobiles, and their demand has been rapidly increasing. Non-oriented electrical steel sheets used in such hybrid cars are required to have high quality and low price. In terms of quality, low iron loss is required, and in terms of price, it is naturally required to be inexpensive.

The use of magnetic steel sheets with low iron loss as iron core materials suppresses temperature rises in electrical equipment caused by heat generation in the iron core and improves the efficiency of the equipment. Iron loss is generally divided into two iron loss components, hysteresis loss and eddy current loss. It is known that these core loss components change depending on metallurgical factors such as the grain size of the steel sheet, the amount of precipitates, the texture, and the electric resistance (specific resistance) of the steel sheet. Metallurgical factors are controlled to reduce iron loss, and can be roughly divided into control of metallurgical factors by annealing conditions or alloy composition conditions, and control of metallurgical factors in rolling.

In the control of metallurgical factors such as annealing conditions or alloy composition conditions, metallurgical factors such as the grain size, amount of precipitates, texture, and electrical resistance (specific resistance) of the steel sheet are controlled from the following viewpoints. be.

As the crystal grain size increases, the hysteresis loss decreases and the eddy current loss increases. Therefore, there is an appropriate grain size that minimizes iron loss. It is known that the proper grain size varies depending on the excitation frequency, and that the higher the frequency, the smaller the proper grain size. Therefore, the proper grain size is selected according to the frequency used. For example, the conditions of the finish annealing are selected so as to obtain the desired suitable grain size.

Precipitates hinder domain wall motion and increase hysteresis loss, and also prevent crystal grains from growing to an appropriate grain size in final annealing, causing an increase in iron loss. Therefore, sulfur component (S) or nitrogen component (N), which form precipitates such as sulfides and nitrides, should be reduced as much as possible.

In addition, in the production of electrical steel sheets, a method of preferentially secondary recrystallization of crystal grains with a preferred orientation during the final finish annealing using a precipitate called an inhibitor is used as a general technique. .

As for the texture, the hysteresis loss can be reduced by increasing the accumulation of the {100} and {110} orientations containing the easy axis of magnetization in the plate plane and decreasing the {111} and {211} orientations not containing the easy axis of magnetization. are decreasing.

An increase in the resistivity of the steel sheet is extremely effective in reducing iron loss because it reduces eddy current loss. In general, the specific resistance of steel sheets is increased by adding Si. However, when the amount of Si added increases, the workability of the electrical steel sheets deteriorates, making them susceptible to breakage during cold rolling. Al is also an element that has a large effect of increasing specific resistance, but like Si, it deteriorates workability. Therefore, if the total amount of Si and Al added exceeds 3%, sheet breakage frequently occurs during rolling, resulting in a decrease in productivity and an increase in manufacturing cost.

On the other hand, in the control of metallurgical factors in rolling, for example, in Patent Document 1, as a technique for controlling metallurgical factors by warm rolling, at the entry side of the stand arranged on the most upstream side in the rolling direction of the tandem rolling mill, A technique of preheating a steel plate to 200° C. or higher and 500° C. or lower and then warm rolling the steel plate is disclosed. Thereby, the texture near the surface layer of the steel sheet is controlled, and the magnetic flux distribution (that is, texture) in the plate thickness direction is made uniform. That is, the hysteresis loss is reduced by increasing the degree of accumulation in the vicinity of the {100} plane of the steel sheet surface layer and homogenizing the magnetic flux distribution (that is, the texture) in the sheet thickness direction.

Various efforts have been made to improve the properties of electrical steel sheets in this way. In particular, a warm rolling method using a tandem rolling mill is attracting attention because it can dramatically improve productivity and reduce manufacturing costs as compared to a rolling method using a Sendzimer rolling mill.

JP 2017-125249 A JP 2006-272382 A JP-A-57-39023

Normally, when rolling an electrical steel sheet by a tandem rolling mill, the raw material (coil) is rolled after heating in a bath called hot bus or after heating with steam because the electrical steel sheet is a brittle material. The temperature of the magnetic steel sheet heated by any heating method is less than 100°C. This method is known to be effective as a countermeasure against brittleness.

However, although these methods are effective as countermeasures against brittleness, since the heating temperature is less than 100° C., the temperature of the electrical steel sheet after heating has the effect of reducing hysteresis loss as described in Patent Document 1. does not reach up to 200° C. Therefore, it is not possible to obtain the effect of increasing the degree of accumulation in the vicinity of the {100} plane of the steel sheet surface layer, homogenizing the magnetic flux distribution (that is, the texture) in the sheet thickness direction, and reducing the hysteresis loss.

By the way, tandem rolling mills used in the cold rolling process are broadly classified into two types, a direct lubrication system and a recirculation lubrication system, in terms of supply of lubricant and cooling of work rolls.

The direct lubrication method is a so-called pouring method. In the direct lubrication system, a lubricating oil emulsion is supplied to the steel plate and work rolls on the entry side of the stand, and a coolant is supplied to the work rolls on the exit side of the stand. These lubricating oils and coolants are recovered, separated and recycled.

A recirculation lubrication system is a circulation system. In the recirculation lubrication system, an emulsion containing a mixture of rolling lubricating oil and water is stored in a tank. On the side, the work rolls are supplied with an emulsion for cooling and cleaning purposes. The supplied emulsion is collected in the tank and reused.

When a preheating device is provided on the upstream side in the rolling direction of such a cold tandem rolling mill to preheat and warm roll the steel sheet, the steel sheet is cooled when the emulsion is applied to the steel sheet. In particular, the first stand located on the most upstream side in the rolling direction of the cold tandem rolling mill has a slower sheet threading speed than the other stands, and the drop in temperature of the steel sheet greatly affects the steel sheet. In order to prevent such cooling of the steel sheet, Patent Document 2, for example, discloses a technique of providing a drain plate so that the coolant supplied to the upper roll of the rolling mill does not splash on the steel sheet.

However, although the provision of a draining plate as described in Patent Document 2 is effective for preventing a decrease in plate temperature, it is not possible to ensure plate-out of the emulsion supplied to the work roll to the steel plate. , insufficient lubrication is likely to occur. For this reason, Patent Document 2 also discloses that the emulsion is made to have a high concentration and supplied to the steel sheet in a small amount in order to eliminate such insufficient lubrication. However, when the emulsion is supplied to the steel plate on the entrance side of the stand, the steel plate is cooled and the temperature of the steel plate is lowered. Therefore, in hot rolling using a preheating device, it is necessary to control the temperature of the preheating device in consideration of the temperature drop of the steel sheet. As the amount of heat to be heated increases, the power consumption of the preheating device also increases, resulting in an increase in manufacturing costs.

On the other hand, when a small amount of high-concentration emulsion is not supplied to the steel sheet for warm rolling, the emulsion introduced into the roll bite is only the emulsion supplied to the work roll, so lubrication Insufficiency causes seizure on the steel plate. When seizure occurs, the surface quality of the steel sheet deteriorates, so the steel sheet is scrapped. Therefore, in order to prevent the steel plate from being seized by supplying a small amount of the emulsion, it is necessary to supply an emulsion with a higher concentration.

However, since excessive lubrication causes slippage, fine control of the emulsion concentration is required. For example, it is not practical to finely control the concentration of the emulsion supplied to the stand by installing a large number of lubricating oil tanks containing emulsions with different concentrations and switching the emulsion to be used depending on the situation.

As a method in which the concentration can be freely changed with a small number of lubricating oil tanks, for example, as disclosed in Patent Document 3, a lubricating oil stock solution and hot water are supplied independently, and the two are mixed immediately before the rolling mill, There is a method of supplying an emulsion using a static mixer. By using such a method, it becomes possible to freely adjust the emulsion concentration within a stable range.

Here, the lubricating oil emulsified by the static mixer and supplied is recovered and regenerated in another process, and then reused as the lubricating oil (undiluted solution). Since high emulsion concentrations lead to high processing and recycling costs, there is a demand for rolling lubrication using emulsions with as low a concentration as possible. On the other hand, it is known that even if the emulsion concentration is the same, the larger the emulsion particle size, the better the plate-out and the better the lubricity. However, the effect of the emulsion particle size on the lubricity is very large, and if it becomes too large, the lubrication becomes excessive and slip is induced. For this reason, conventional static mixers can only be applied when the average particle size of the emulsion is in the range of 8 to 20 μm, and there is a limit to the improvement of lubricity at low concentrations.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to ensure lubricity when a steel plate is warm-rolled by a cold tandem rolling mill of a direct circulation system. To provide a new and improved rolling facility and rolling method capable of supplying a low-concentration emulsion capable of preventing seizure.

In order to solve the above problems, according to one aspect of the present invention, there is provided a preheating device for heating a steel plate, and a direct lubricating type cooling device arranged downstream of the preheating device in the rolling direction and composed of a plurality of stands. and a cold tandem rolling mill, and one stand arranged on the upstream side in the rolling direction of the stands constituting the cold tandem rolling mill is arranged on the entry side of the stand, and the work roll of the stand an emulsion supply nozzle that supplies an emulsion to the stand, a cooling liquid supply nozzle that is arranged on the exit side of the stand and supplies cooling liquid to the work roll, and an emulsion supply nozzle that is arranged at least on the entry side of the stand A draining plate arranged between the plate and the steel plate, and an emulsion adjustment facility for adjusting the emulsion supplied from the emulsion supply nozzle are provided, and the emulsion adjustment facility mixes hot water and lubricating oil to form an emulsion. a static mixer that generates a, a particle size measuring device that measures the emulsion particle size of the emulsion generated by the static mixer, and a flow rate that controls the emulsion supply flow rate based on the measured value of the emulsion particle size by the particle size measuring device A rolling facility is provided, including a controller.

The steel sheet is an electromagnetic steel sheet, and the preheating device preheats the electromagnetic steel sheet so that the sheet temperature of the electromagnetic steel sheet is 200° C. or more and 500° C. or less on the entry side of the cold tandem rolling mill. Alternatively, the electrical steel sheet may be rolled at least at the first stand on the most upstream side in the rolling direction at a rolling reduction of 30% or more.

The work rolls of the stand provided with the emulsion conditioning facility may have a roll profile in which at least one of the upper and lower work rolls near the plate edge gradually decreases in diameter toward the roll edge.

Moreover, the work roll of the stand provided with the emulsion adjustment equipment may be a high-speed roll.

Further, the work roll of the stand provided with emulsion conditioning equipment may have a surface roughness of 0.6 to 1.2 μmRa.

The stand provided with the emulsion conditioning facility may have a cooling mechanism for cooling the bearings of the chocks that support the work rolls.

In order to solve the above problems, according to another aspect of the present invention, there is provided a preheating device for heating a steel sheet, and a direct lubricating device, which is arranged downstream in the rolling direction with respect to the preheating device and consists of a plurality of stands. A cold tandem rolling mill of the type A rolling method by a rolling facility having a an emulsion supply nozzle arranged on the side and supplying emulsion to the work roll of the stand; a cooling liquid supply nozzle arranged on the exit side of the stand and supplying cooling liquid to the work roll; and at least the stand A draining plate arranged on the inlet side of the emulsion supply nozzle and the electromagnetic steel sheet, and an emulsion adjustment facility for adjusting the emulsion supplied from the emulsion supply nozzle are provided, and the emulsion adjustment facility is , a static mixer that mixes hot water and lubricating oil to generate an emulsion, a particle size measuring device that measures the emulsion particle size of the emulsion generated by the static mixer, and the measured value of the emulsion particle size by the particle size measuring device. and a flow control device for controlling the supply flow rate of the emulsion, and in a stand provided with emulsion adjustment equipment, the particle size measurement device measures the emulsion particle size of the emulsion generated by the static mixer, By the control device, the measured value of the emulsion particle size, the emulsion particle size obtained in advance, the emulsion concentration, the supply flow rate, and the friction coefficient are adjusted so that the friction coefficient between the work roll and the steel plate is within a predetermined range. A rolling method is provided that controls the feed flow rate of the emulsion based on the relationship.

As described above, according to the present invention, when a steel plate is warm-rolled by a cold tandem rolling mill of a direct circulation system, an emulsion having as low a concentration as possible is supplied to ensure lubricity and prevent seizure. be able to.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic explanatory drawing which shows an example of the steel plate manufacturing process which concerns on one Embodiment of this invention. It is a schematic diagram which shows one structural example of the stand provided with the emulsion adjustment equipment which concerns on the same embodiment. FIG. 2 is a schematic diagram showing an example of a work roll having tapered roll ends. 1 is a graph showing the relationship between emulsion particle size, emulsion concentration, supply flow rate, and friction coefficient. It is a flowchart which shows the process which calculates the supply flow volume of the emulsion supplied to a work roll.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and drawings, constituent elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

<1. Structure of Steel Plate Manufacturing Process>
First, a steel sheet manufacturing process 1 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic explanatory diagram showing an example of a steel plate manufacturing process 1 according to this embodiment.

In this embodiment, as steel sheet manufacturing process 1, a manufacturing process of a non-oriented electrical steel sheet (hereinafter also simply referred to as an electrical steel sheet S) will be described. In this embodiment, the non-oriented electrical steel sheet has, in mass %, 2.5%≦Si≦5.0%, 0.1%≦Al≦2.0%, and 0.1%≦Mn≦2.0%. %, P≤0.02%, 0.001%≤C≤0.005%, 0.001%≤N≤0.005%, S≤0.005%, Cu≤0.1%, Ni≤0 A steel sheet containing .1% and the balance containing Fe and impurity elements. The present invention also includes non-oriented electrical steel sheets that do not contain the elements P, S, Cu, and Ni. The non-oriented electrical steel sheet according to the present embodiment is a steel sheet containing Si, Al, Mn, P, C, N, S, Cu and Ni in the above ranges and the balance being Fe and impurity elements. desirable. Moreover, the present invention can be applied not only to the production of non-oriented electrical steel sheets, but also to the production of grain-oriented electrical steel sheets and high-tensile steel.

For example, as shown in FIG. 1, the steel plate manufacturing process 1 includes a coil dispenser 10, a welding machine 20, a looper 30, a pickling equipment 40, a preheating device 50, a cold tandem rolling mill 60, and a cutting machine 70 and coil winder 80. In the steel sheet manufacturing process 1, a hot-rolled non-oriented electrical steel sheet or a heat-treated non-oriented electrical steel sheet coil (hereinafter collectively referred to as an "electromagnetic steel sheet") is processed after being hot-rolled. do. FIG. 1 shows a state in which non-oriented electrical steel sheet coils C1 and C2 are supplied to a coil dispensing machine 10 and non-oriented electrical steel sheet coil C2 is dispensed.

The coil dispenser 10 dispenses the coils C1 and C2 of the supplied electromagnetic steel sheet S, and supplies the electromagnetic steel sheet S to equipment on the downstream side. In addition, the coil supplied to the coil dispenser 10 may be preheated to 60° C. or higher by a hot bath or the like.

The welding machine 20 welds the tail end of the electromagnetic steel sheet S of the preceding coil supplied from the coil dispenser 10 and the leading end of the electromagnetic steel sheet S of the following coil. As a result, the electromagnetic steel sheet S is made into a continuous strip. The electromagnetic steel sheets S made into strips are sent to the looper 30 .

The looper 30 is equipment for controlling the transportation of the electromagnetic steel sheets S so that the supply of the electromagnetic steel sheets S does not become stagnant in the downstream process. For example, when the conveying of the electromagnetic steel sheets S is stopped because the welding machine 20 is performing coil joining, the conveying distance of the electromagnetic steel sheets S by the looper 30 is controlled so that the supply of the electromagnetic steel sheets S to the downstream process does not change. be done. The electromagnetic steel sheet S that has passed through the looper 30 is supplied to the pickling equipment 40 .

The pickling equipment 40 removes scales from the surface of the electromagnetic steel sheet S that has been hot rolled or heat-treated after hot rolling. A pickling tank of the pickling equipment 40 contains a pickling liquid. The pickling liquid is, for example, an aqueous solution such as hydrochloric acid or sulfuric acid capable of scraping off scale. In the pickling equipment 40, the scale on the surface of the electromagnetic steel sheet S is shaved off by conveying the electromagnetic steel sheet S while being immersed in a pickling solution in a pickling bath. In order to increase the cutting efficiency of the pickling, on the upstream side of the pickling equipment 40, a rolling mill for cracking the scale on the surface of the electromagnetic steel sheet S, a leveler device, a tension leveler, and a dry or wet shot blaster are provided. , or a grinder or the like may be installed. The electromagnetic steel sheet S pickled by the pickling equipment 40 to remove scales from the surface is supplied to the preheating device 50 .

The preheating device 50 heats the pickled electromagnetic steel sheet S before being rolled by the cold tandem rolling mill 60 . The heating form of the electromagnetic steel sheet S by the preheating device 50 is not particularly limited. For example, an induction heating device may be used as the preheating device 50 . The preheating device 50 heats the electrical steel sheet S so that the temperature of the steel sheet on the entry side of the cold tandem rolling mill 60 is 200° C. or more and 500° C. or less. Thereby, the effect of reducing the hysteresis loss of the electrical steel sheet S can be enhanced. The electromagnetic steel sheet S heated by the preheating device 50 is supplied to the cold tandem rolling mill 60 and rolled.

Here, the heating temperature of the electromagnetic steel sheet S by the preheating device 50 can be determined based on the distance between the preheating device 50 and the cold tandem rolling mill 60 and the like. For example, the distance between the preheating device 50 and the cold tandem rolling mill 60 is 10 m, and the threading speed is 150 m/min. , the plate temperature of the electromagnetic steel plate S decreases by about 50° C. while passing through the section. Therefore, the heating temperature of the electromagnetic steel sheet S by the preheating device 50 may be determined in consideration of the decrease in the sheet temperature.

At the entry side of the cold tandem rolling mill 60, a thermometer (not shown) for measuring the surface temperature (plate temperature) of the electromagnetic steel sheet S is installed. The preheating device 50 controls the output power based on the temperature of the magnetic steel sheet S measured by the thermometer so that the magnetic steel sheet S reaches a preset target temperature.

The cold tandem rolling mill 60 rolls the electromagnetic steel sheet S to a predetermined target thickness. The cold tandem rolling mill 60 according to the present embodiment is arranged on the downstream side in the rolling direction with respect to the preheating device 50, and is a direct lubrication type cold tandem rolling mill comprising a plurality of stands 6a to 6f. For example, the first stand 6a to the fifth stand 6e on the most upstream side in the rolling direction may be a quadruple rolling stand, and the sixth stand 6f on the most downstream side in the rolling direction may be a six-fold rolling stand. Specifically, in a quadruple rolling stand, for example, the work roll diameter may be 500 mm to 700 mm, the backup roll diameter may be 1300 mm to 1600 mm, and the barrel length may be 2000 mm. In a six-fold rolling stand, for example, the work roll diameter may be 450 mm to 500 mm, the intermediate roll diameter may be 500 mm to 650 mm, the backup roll diameter may be 1300 mm to 1500 mm, and the barrel length may be 2000 mm.

Although the cold tandem rolling mill 60 shown in FIG. 1 comprises six stands 6a to 6f, the present invention is not limited to such an example, and at least four or more stands may be provided. The cold tandem rolling mill 60 rolls, for example, a non-oriented electrical steel sheet having a thickness of 2.3 mm and a width of 1200 mm to a thickness of 0.3 mm. The electrical steel sheet S rolled by the cold tandem rolling mill 60 is coiled by a coil winder 80, which will be described later.

Here, the cold tandem rolling mill 60 according to the present embodiment is provided with emulsion adjustment equipment for the first stand 6a among these stands 6a to 6f. The emulsion conditioning facility makes it possible to control the supply flow rate of the emulsion supplied to the work rolls based on the emulsion particle size of the emulsion supplied to the stand. The details of the emulsion adjustment equipment will be described later.

In addition, direct lubrication rolling is also performed in the second stand 6b to the sixth stand 6f, and emulsion of a predetermined concentration is supplied from the tank toward the roll bite from the entry side of each stand. In addition, cooling liquid is supplied to the work rolls from the exit side of each stand to cool the work rolls. The supplied emulsion and cooling liquid are recovered, separated into oil and water in another line, and regenerated. Note that the second stand 6b to the sixth stand 6f may not be provided with emulsion adjustment equipment, which will be described later.

A cutting machine 70 and a coil winding machine 80 are installed downstream of the cold tandem rolling mill 60 in the rolling direction. The cutting machine 70 cuts the continuous electromagnetic steel sheet S. As shown in FIG. A carousel reel for winding the electromagnetic steel sheet S is arranged as a coil winder 80 on the downstream side of the cutting machine 70 in the rolling direction. The coil of the electromagnetic steel sheet S wound into a coil shape by the coil winder 80 and cut into a predetermined length by the cutting machine 70 is discharged from the coil winder 80 and transferred to the next process by a conveyor. and carried out.

<2. Emulsion adjustment equipment>
The cold tandem rolling mill 60 according to the present embodiment adjusts the emulsion concentration in order to supply a low-concentration emulsion that can ensure lubricity and prevent seizure when warm-rolling an electrical steel sheet. Equipped with emulsion adjustment equipment. The emulsion adjustment equipment measures the grain size of the emulsion supplied to the stand, and adjusts the measured value of the grain size of the emulsion and the previously acquired Based on the obtained emulsion particle size, emulsion concentration and the relationship between the supply flow rate and the coefficient of friction, the supply flow rate of the emulsion is controlled. As a result, the concentration of the emulsion to be used is kept low, lubricity is ensured, and the occurrence of seizure is prevented. The configuration of the emulsion conditioning equipment and the rolling in the stand in which the emulsion conditioning equipment is installed will be described below.

[2-1. Constitution]
FIG. 2 shows a configuration example of a stand provided with emulsion adjustment equipment according to the present embodiment. In this embodiment, it is assumed that the first stand 6a is provided with emulsion adjustment equipment. However, the present invention is not limited to such an example, and the emulsion adjustment equipment may be provided in a stand arranged on the upstream side in the rolling direction, for example, it may be provided in the second stand 6b.

As shown in FIG. 2, the first stand 6a includes an upper work roll 61a and a lower work roll 61b, and an upper backup roll 62a and a lower backup roll 62b that support the pair of work rolls 61a and 61b. The electromagnetic steel sheet S is rolled to a predetermined thickness by passing between a pair of work rolls 61a and 61b.

Here, the upper work roll 61a and the lower work roll 61b may both be flat rolls. Alternatively, at least one of the upper and lower sides may have a roll profile in which the diameter gradually decreases toward the roll end in the vicinity of the plate end. For example, as shown in FIG. 3, the vicinity of the plate end portions of the upper work roll 61a and the lower work roll 61b may have a so-called tapered shape in which the diameters gradually decrease toward the roll ends. Thereby, the edge drop of the electromagnetic steel sheet S can be controlled. If the upper and lower work rolls 61a and 61b are movable in the strip width direction, only one side of the work rolls 61a and 61b in the trunk length direction is formed into a so-called tapered shape, and the upper and lower work rolls 61a and 61b are turned. They may be arranged symmetrically. In such a rolling mill, by moving the upper and lower work rolls 61a and 61b in the width direction of the sheet according to the sheet width, it is possible to roll the magnetic steel sheet S with the taper-shaped position corresponding to the sheet end portion. .

Also, the upper work roll 61a and the lower work roll 61b may be HSS rolls. HSS rolls are rolls with high abrasion resistance, and have excellent high-temperature strength and surface roughening resistance. As the material of the high speed roll, for example, E61 in which MC, M ₂ C, and M ₆ C are dispersed in the matrix as primary carbides may be used.

Furthermore, the upper work roll 61a and the lower work roll 61b may have a surface roughness of 0.6 to 1.2 μmRa. By setting the surface roughness of the work rolls 61a and 61b within the above range, the pickling treatment by the pickling equipment 40 upstream of the cold tandem rolling mill 60 causes uneven pickling on the surface of the electromagnetic steel sheet S. Variations in properties can be made uniform. In addition, the effect of additional shear strain can be exerted during deformation in the roll bite, and the quality can be improved. Forged steel rolls may be used as the upper work roll 61a and the lower work roll 61b.

Moreover, the chocks that support the upper work roll 61a and the lower work roll 61b are provided with bearings that rotatably support the roll shafts provided on the respective chocks. Therefore, the chocks supporting the upper work roll 61a and the lower work roll 61b according to the present embodiment may be provided with a cooling mechanism for cooling the bearings in the chocks. This effectively cools the chock and, for example, in grease-encapsulated bearing lubrication, can also prevent grease from melting, leaking, and concomitant seizure of the bearing.

Cooling of the bearings may, for example, be accompanied by lubrication of the bearings. Lubrication methods for bearings include, for example, forced lubrication, oil mist lubrication, air-oil lubrication, and jet lubrication. By providing the bearing with a mechanism for realizing these lubrication methods as a cooling mechanism, it is possible to obtain a cooling effect for the bearing. Alternatively, the bearing may be cooled by directly supplying a cooling medium such as water or air from the outside of the chock. The bearing can also be cooled by, for example, installing a pipe or the like inside the chock and circulating a cooling medium such as water or air through the pipe.

At the entry side of the first stand 6a having such work rolls 61a, 61b and backup rolls 62a, 62b, an emulsion prepared by mixing warm water and lubricating oil is applied to the work rolls 61a, 62b by a static mixer 95, which will be described later. Emulsion supply nozzles 63a and 63b are provided to supply to 61b. By supplying the emulsion to the work rolls 61a and 61b from the emulsion supply nozzles 63a and 63b, the plate-out on the surfaces of the work rolls 61a and 61b is increased, and the lubricity between the work rolls 61a and 61b and the electromagnetic steel sheet S ensure The supply of emulsion also contributes to the cooling of the work rolls 61a, 61b.

Between the emulsion supply nozzles 63a, 63b and the electromagnetic steel sheet S, draining plates 64a, 64b are arranged. By providing the draining plates 64a and 64b, the emulsion supplied from the emulsion supply nozzles 63a and 63b can be prevented from being applied to the electromagnetic steel sheet S, and the temperature of the electrical steel sheet S can be prevented from decreasing. It can suppress the occurrence. By preventing the plate temperature from dropping, it is possible to suppress variations in the quality of the final product, such as iron loss. In addition, by suppressing the occurrence of temperature unevenness, it is also suppressed that the shape of the steel sheet becomes defective due to rolling in the cold tandem rolling mill 60, and as a result, the induction of strip breakage or meandering due to drawing is also suppressed. be.

Coolant supply nozzles 65a and 65b for supplying coolant to the work rolls 61a and 61b are provided on the exit side of the first stand 6a. Coolant supply nozzles 65a and 65b supply coolant such as water to the work rolls 61a and 61b to cool the work rolls 61a and 61b. Although not shown in FIG. 2, the cooling liquid supplied to the work rolls 61a and 61b is also supplied to the delivery side of the first stand 6a in the same manner as the inlet side so that the cooling liquid supplied to the work rolls 61a and 61b does not splash on the electromagnetic steel sheet S. A draining plate may be installed between the nozzles 65a and 65b and the electromagnetic steel plate S.

Also, the first stand 6 a is provided with emulsion adjustment equipment including a static mixer 95 , a particle size measuring device 97 and a flow control device 100 .

The static mixer 95 produces emulsion supplied from the emulsion supply nozzles 63a, 63b. The static mixer 95 is a device for mixing the lubricating oil undiluted solution and warm water stored independently of each other immediately before supplying them to the work rolls 61a and 61b.

More specifically, as shown in FIG. 2, the emulsion adjustment facility comprises a first tank 91 that heats and stores the undiluted lubricating oil, and a second tank 92 that stores hot water. Palm oil, for example, may be used as a lubricating oil. Lubricants are stored, for example, at about 50°C. Alternatively, the hot water may be pure water, for example, and is stored in the second tank 92 at, for example, about 50.degree. The lubricating oil stock solution stored in the first tank 91 is supplied to the static mixer 95 by the first pump 93 , and the hot water stored in the second tank 92 is supplied to the static mixer 95 by the second pump 94 . supplied.

The static mixer 95 shears the undiluted lubricating oil supplied from the first tank 91 and the hot water supplied from the second tank 92 with fins (not shown) provided inside to form an emulsion. do. The concentration of the generated emulsion is adjusted by changing the ratio between the flow rate of the undiluted lubricating oil supplied by the first pump 93 and the flow rate of the hot water supplied by the second pump 94 . The rate of flow and each flow are controlled by the flow controller 100 .

The particle size of the emulsion prepared using the static mixer 95 is measured by the particle size measuring device 97, and then supplied from the emulsion supply nozzles 63a, 63b to the work rolls 61a, 61b. As the particle size measuring device 97, for example, a laser diffraction particle size distribution measuring device can be used. The particle size measuring device 97 outputs the measured value of the emulsion particle size to the flow control device 100 .

The flow rate control device 100 adjusts the ratio of the flow rates of the lubricating oil undiluted solution and the warm water so that the concentration of the emulsion generated by the static mixer 95 becomes an appropriate value according to the measured value of the emulsion particle size by the particle size measuring device 97. and control each flow rate.

[2-2. Adjustment of emulsion]
In determining the ratio of the flow rate of the undiluted lubricating oil to the hot water by the flow control device 100, first, the relationship between the emulsion particle size, the emulsion concentration, the supply flow rate, and the friction coefficient was investigated. FIG. 4 shows the relationship between emulsion particle size, emulsion concentration, supply flow rate, and friction coefficient. In FIG. 4, the feed flow rate and friction coefficient for three cases: 20% emulsion concentration and an emulsion particle size of about 15 μm, and 10% emulsion concentration and an emulsion particle size of about 50 μm and about 100 μm. It shows the relationship with The rolling speed of the magnetic steel sheet S was set to 200 m/min.

In addition, as described above, the emulsion is usually used with an average particle size in the range of about 8 to 20 μm in order to ensure emulsification stability. For example, the emulsion supply nozzles 63a and 63b supply an emulsion having an emulsion concentration of 5 to 15% to the work rolls 61a and 61b at a supply rate of about 10 to 50 liters/min. Under such conditions, the emulsion particle size does not change abruptly. From this, it can be considered that the emulsion particle size is constant within the supply flow rate range shown in FIG.

In FIG. 4, the appropriate range (0.06 to 0.08) of the coefficient of friction is indicated by hatching. If the coefficient of friction is less than the lower limit of the appropriate range, slippage is likely to occur, and if the coefficient of friction is greater than the upper limit of the appropriate range, seizure will occur. Therefore, the flow rate control device 100 determines the supply flow rate according to the emulsion particle size and the emulsion concentration so that the friction coefficient is within the appropriate range. As shown in FIG. 4, by increasing the emulsion particle size to 50 μm and 100 μm, even if a small amount of low-concentration emulsion is supplied, the coefficient of friction is within an appropriate range, and plate-out can be ensured. However, even if the emulsion concentration is the same, if the emulsion particle size is different, the supply flow rate required for the friction coefficient to be within the appropriate range will be different. As described above, since the emulsion particle size has a great influence on the plate-out, it is necessary to strictly control the emulsion particle size and the supply flow rate.

Therefore, the flow rate control device 100 according to the present embodiment calculates the supply flow rate of the emulsion to be supplied to the work rolls 61a and 61b based on the processing flow shown in FIG.

First, before starting rolling, the relationship between the emulsion particle size, emulsion concentration, supply flow rate, and friction coefficient is acquired in advance (S10). Since these relationships change depending on the rolling speed, they are obtained for each rolling speed.

When the cold tandem rolling mill 60 starts rolling, the grain size of the emulsion produced by the static mixer 95 is measured by the grain size measuring device 97 (S20). The particle size measuring device 97 outputs the measured value of the emulsion particle size to the flow control device 100 .

When the measured value of the emulsion particle size is input, the flow control device 100 identifies the relationship corresponding to the current emulsion particle size and emulsion concentration from the relationship previously acquired in step S10 (S30). The emulsion concentration can be specified by the ratio between the flow rate of the undiluted lubricating oil supplied by the first pump 93 and the flow rate of the warm water supplied by the second pump 94, and the ratio of such flow rates is determined by the flow rate control device 100. This is information set by If the current emulsion particle size and emulsion concentration are known, it is possible to uniquely identify the relationship between the emulsion particle size, emulsion concentration, supply flow rate, and friction coefficient as shown in FIG. 4, for example.

Then, based on the relationship specified in step S30, the flow control device 100 obtains the supply flow rate of the emulsion at which the coefficient of friction is within the appropriate range for the emulsion particle size and the emulsion concentration measured by the particle size measuring device 97. . Then, the flow control device 100 controls the first pump 93 and the second pump 94 so that the emulsion is supplied to the work rolls 61a and 61b at the obtained supply flow rate (S40).

For example, when the relationship shown in FIG. 4 is obtained, when the emulsion concentration is 10% and the emulsion particle size is about 50 μm, the emulsion supply flow rate can be reduced to about 14 liters/min, and the emulsion concentration is 10% and the emulsion particle size is about 100 μm, the emulsion feed rate can be reduced to about 12 liters/min. As described above, by using the emulsion adjustment equipment according to the present embodiment, it is possible to reduce the concentration of the emulsion used during rolling, ensure lubricity, and prevent the occurrence of seizure.

When determining the flow rate of the emulsion to be supplied so that the coefficient of friction falls within the proper range, the flow rate control device 100 arbitrarily sets a target value within the proper range of the coefficient of friction so that the coefficient of friction becomes the target value. You may set the supply flow volume of an emulsion. For example, when the appropriate range of the friction coefficient is 0.06 to 0.08, the target value of the friction coefficient is set to 0.07, and the supply flow rate of the emulsion is adjusted so that the friction coefficient falls within 0.07 ± 0.005. May be set.

The following verification was performed in order to verify the effects of the present invention. In this example, the following Comparative Examples 1 and 2 and Example 1 were examined for the presence or absence of slip and seizure when the magnetic steel sheets were rolled by changing the rolling conditions in the steel sheet manufacturing process shown in FIG.

In this verification, a non-oriented electrical steel sheet having a thickness of 2.3 mm and a width of 1200 mm was used and rolled to a thickness of 0.3 mm by a cold tandem rolling mill. The plate temperature at the entry side of the first stand was 450° C., the rolling reduction was 38%, and the rolling speed was 200 m/min. Palm oil was used as the lubricating oil. Further, on the delivery side of the first stand, cooling water was supplied to the work roll from a cooling liquid supply nozzle to cool the work roll.

In Comparative Example 1, the emulsion grain size was not measured, and the magnetic steel sheet was rolled while lubricating with an emulsion concentration of 10% and a supply flow rate of 20 liters/min. In Comparative Example 2, the emulsion grain size was not measured, and the electrical steel sheet was rolled while lubricating at an emulsion concentration of 20% and a supply flow rate of 20 liters/min.

On the other hand, in Example 1, based on the processing shown in FIG. Based on the relationship, the supply flow rate of the emulsion was adjusted so that the coefficient of friction was within the appropriate range. In Example 1, the emulsion particle size was 75 μm, the emulsion concentration was 10%, and the supply flow rate of the emulsion was set to 15 liters/min from the relationship with the previously obtained friction coefficient.

Comparative Examples 1 and 2 and Example 1 were subjected to rolling by a cold tandem rolling mill. As a result, in Comparative Example 1, seizure occurred, and slip occurred during rolling. In Comparative Example 22, seizure could be prevented, but slip occurred during rolling. On the other hand, in Example 1, neither seizure nor slip occurred, and these problems could be completely prevented. In Example 1, the supply flow rate could be reduced compared to Comparative Example 1 with the same emulsion concentration. Moreover, in comparison with Comparative Example 2, in Example 1, the emulsion concentration was reduced and the supply flow rate was also reduced.

As described above, when rolling a non-oriented electrical steel sheet with a direct lubrication type cold tandem rolling mill, the non-oriented electrical steel sheet is preheated so that the sheet temperature is 200 ° C. or higher and 500 ° C. or lower, and then at least rolling It was confirmed that the cost of the emulsion can be reduced and the occurrence of seizure can be prevented by applying the rolling method of the present invention when rolling at the first stand on the most upstream side in the direction at a rolling reduction of 30% or more.

Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention belongs can conceive of various modifications or modifications within the scope of the technical idea described in the claims. It is understood that these also naturally belong to the technical scope of the present invention.

For example, in the above embodiments, the case of applying to rolling of a non-oriented electrical steel sheet has been described, but the present invention is not limited to such an example. For example, it may be applied to rolling for grain-oriented electrical steel sheets and high-tensile steels. In the case of high-tensile steel, warm rolling can reduce the load during rolling and prevent sheet breakage.

1 Steel plate manufacturing process 6a to 6f 1st to 6th stands 10 coil dispensing machine 20 welding machine 30 looper 50 preheating device 60 cold tandem rolling mill 61a upper work roll 61b lower work roll 62a upper backup roll 62b lower backup roll 63a, 63b Emulsion supply nozzle 64a, 64b Draining plate 65a, 65b Coolant supply nozzle 70 Cutting machine 80 Coil winder 91 First tank 92 Second tank 93 First pump 94 Second pump 95 Static mixer 97 Particle size Measuring device 100 flow control device

Claims (7)

a preheating device for heating the steel plate;
a direct lubrication type cold tandem rolling mill, which is arranged on the downstream side in the rolling direction with respect to the preheating device and is composed of a plurality of stands;
has
Among the stands constituting the cold tandem rolling mill, the first stand or the second stand has
an emulsion supply nozzle arranged on the entrance side of the stand and supplying the emulsion to the work roll of the stand;
a cooling liquid supply nozzle arranged on the exit side of the stand for supplying cooling liquid to the work roll;
a draining plate disposed at least on the entrance side of the stand and disposed between the emulsion supply nozzle and the steel plate;
an emulsion adjustment facility for adjusting the emulsion supplied from the emulsion supply nozzle;
is provided,
The emulsion adjustment equipment is
a static mixer that mixes hot water and lubricating oil to form an emulsion;
a particle size measuring device for measuring the emulsion particle size of the emulsion generated by the static mixer;
a flow control device for controlling the supply flow rate of the emulsion based on the measured value of the emulsion particle size by the particle size measuring device;
rolling equipment, including; The steel plate is an electromagnetic steel plate,
The preheating device preheats the magnetic steel sheet so that the temperature of the magnetic steel sheet is 200° C. or more and 500° C. or less on the entry side of the cold tandem rolling mill,
The rolling facility according to claim 1, wherein the cold tandem rolling mill rolls the electrical steel sheet at least at the first stand on the most upstream side in the rolling direction at a rolling reduction of 30% or more. 3. The work rolls of the stand provided with the emulsion adjusting equipment have a roll profile in which at least one of the upper and lower work rolls has a roll profile in which the diameter gradually decreases toward the roll end in the vicinity of the plate end. The rolling equipment described in . The rolling facility according to any one of claims 1 to 3, wherein the work rolls of the stand provided with the emulsion adjustment facility are high-speed steel rolls. The rolling equipment according to any one of claims 1 to 4, wherein the work rolls of the stand provided with the emulsion adjustment equipment have a surface roughness of 0.6 to 1.2 µmRa. The rolling facility according to any one of claims 1 to 5, wherein said stand provided with said emulsion conditioning equipment has a cooling mechanism for cooling bearings of chocks supporting said work rolls. A rolling method using a rolling facility having a preheating device that heats a steel plate, and a direct lubrication type cold tandem rolling mill that is arranged on the downstream side of the preheating device in the rolling direction and consists of a plurality of stands, ,
Among the stands constituting the cold tandem rolling mill, the first stand or the second stand has
An emulsion supply nozzle arranged on the entrance side of the stand to supply emulsion to the work roll of the stand, and a coolant supply nozzle arranged on the exit side of the stand to supply the coolant to the work roll. , a draining plate arranged at least on the entrance side of the stand and arranged between the emulsion supply nozzle and the steel plate, and emulsion adjustment equipment for adjusting the emulsion supplied from the emulsion supply nozzle. and
The emulsion adjustment equipment is
A static mixer that mixes hot water and lubricating oil to generate an emulsion, a particle size measuring device that measures the emulsion particle size of the emulsion generated by the static mixer, and measurement of the emulsion particle size by the particle size measuring device. a flow controller that controls the supply flow rate of the emulsion based on the value;
In the stand provided with the emulsion adjustment equipment,
Measure the emulsion particle size of the emulsion generated by the static mixer with the particle size measuring device,
By the flow control device, the measured value of the emulsion particle size, the emulsion particle size obtained in advance, the emulsion concentration and the supply flow rate are adjusted so that the coefficient of friction between the work roll and the steel plate is within a predetermined range. A rolling method, wherein the supply flow rate of the emulsion is controlled based on the relationship with the coefficient of friction.

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